Combination random-probability system



Nov. 7, 1961 H. F. oLsoN Erm.

COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5. 1954 17 Sheets-Sheet 1 irraf/vf/ Nov. 7, 1961 H. F.A OLSON ETAL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5. 1954 17 Sheeizs-SheeiI 2 MSX QS H H w Nov. 7, 1961 H. F. OLSON TAL COMBINATION RANDOM-PROBABILITY SYSTEM y irraeA/:Y

Nov. 7, 1961 H. F. OLSON ET AL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed OCt. 5. 1954 17 Sheets-Sheet 4 All Nov. 7, 1.961 H. F. oLsoN ET AL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Nov. 7, 1961 H. F. OLSON ET AL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5. 1954 1,7 Sheets-Sheet 6 437- 19' //wrf wf- 305 1w@ r; //s @Worf f f Z2 /4 z d a i7 e A ..5 e c f* 25 PW? 4 b d 29 6 ,4 f 30 6*,4 a a .3f ,4 A 7 D 0./ .52 5 f4 s Ffa! 35 D A A .34 .E A /0 D al if ,M5 d e a@ g /Z ef 37 f; g /5 F e ii f4 da; z 5;; /5 e pff# 4f d C f f7 6 F# 4f D C# /5 A F# 45 i C# 75 F# 44 af D 2'@ d 6 4i D 2/ if@ 46 A D 22 G 47 D D 2s A a 4i @"0 f4 ,5 6 49 D D 2j A G# 50 D E Mm'.- Uf im? mi acm/f ,4f/6fm r//Af/ an/f@ Diff INVENTOR5 #may f' 01m/y ,e #fuif/*15H45 Nov. 7? 1961 H. F. oLsoN ETAL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed om. 5. 1954 yr sheets-sheet fr @as ,cw/ars l @#0/ e @GMA 5w@ E IN VEN TOR5 HARRY 0L scr/v a BY HfRERr HRR ,4r TORA/E Y Nov. 7, i961 H. F. OLSON ETAL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed OCt. 5, 1954 17 Sheets-Sheet 8 gasp/NOTE .c#def"6GA DE 2G a 2 GA 4. 5 B 16 D' EA E C# @Wm/M caw/FOL #Mawr/0N WAI-EK 4/4 V4 Mams/my 1445 J J J J J 4/1@ 144C JJJ .J J J Ze 144D JJ J J J 2A@ |445 JJ J J J 2A@ i441 .1J .l J .J Z/r INVENTORS HA FRY OLSON Awa I?? I0 BY /mier 5am? Nov. 7, 1961 H. F. oLsoN ETAL COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5. 1954 Nov. 7, 1961 H. F. OLSON ETAL.

coMBNATIoN RANDoM-PRoBABLITY SYSTEM 1,7 Sheets-Sheet 10 Filed Oct. 5, 1954 Nov. 7, 1961 H. F. OLSON ETAL COMBINATION RANDOM-PROBABILITY SYSTEM 17 Sheets-Sheet 11 Filed Oct. 5, 1954 Nom 7, 1961 H. F. OLSON ETAL COMBINATION RANDOM-PROBABILITY SYSTEM Filed 001.. 5, 1954 17 Sheets-Sheet 12 Nov. 7, 1961 H. F. OLSON ETAL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5, 1954 17 Sheets-Shea?l 13 2/4 caff/mv Zl Ron/4- KOP/.5 mf? ,4 TTU/iwf Y Nov. 7, 1961 H. F. OLSON ETAL COMBINATION RANDOM-PROBABILITY SYSTEM Filed oct. 5. 1954 17 Sheets-Sheet x4 ,n l l l l l l f l l l l n! y M .m N r mi Ne ai uw.. |l :,.r W y a n L |NNN|||1 1|@ 1| H f x. w

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COMBINATION RANDOM-PROBABILITY SYSTEM 17 Sheets-Shea?l 15 N0v.7,1961y Filed OCt. 5, 1954 I. l l l l l I L Nov. 7, 1961 H. F. oLsoN ETAL 3,007,362

COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5. 1954 1'7 Sheets-Sheet 16 wf may mi ,Wgl @if 224, ZM l Z771 I 2 Q 22e., i l

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COMBINATION RANDOM-PROBABILITY SYSTEM Filed Oct. 5. 1954 17 Sheets-Sheet 1'? i can/rm /if y HZ'TOKA/FY United States Patent O 3,007,362 COMBINATION RANDOM-PROBABILITY SYSTEM v t Harry F. Olson, Princeton, and Herbert Belar, Palmyra, NJ., assignors to Radio Corporation of America, a corporation of Delaware v Filed Oct. 5, 1954, Ser. No. 460,396 37 Claims. .(Cl. Sil- 1.03)

`Our invention relates to methods and apparatus which automatically supply information to create events following each other in sequence, particularly such special cases of sequences of events, where the probability of any type event occurring depends upon the kind of event or events that preceded. An event may be a musical tone, a pattern, a value, a number or an item of information, as will be described hereinafter. Such methods and apparatus represent a muchhigher order of organization than methods and apparatus for producing Ia series of random numbers as would a roulette wheel, for instance. While some processes in nature probably are purely random, there are more thaft are not in that what has taken place before is known to affect the future probability. The patter of rain may be random but the probability of raining is aifected by the preceding weather. The specific example of the invention hereinafter described is -a music composing machine and a method of composing music. Further, 'the specific example of said machine is designed to compose a sequence of successive notes of the same statistical character as employed in the compositions of Stephen Foster.

It will aid in understanding the present invention to note that there are commonly in use two methods or types of apparatus in the mathematical, computing or calculating field. The most common method is represented by a computing machine which gives one specific correct answer when certain values lare set into it. The second method is represented bythe method or apparatus that utilizes probabilities but still provides -a single answer which is the best answer based on the probabilities. For example, in fire control, based on past performance and other factors it can be calculated what is the most likely position of a target. lAs another example, in operations research the probability of various -events occurringform the basis of devising the best strategy. Similarly, in the theory of games, probabilities are utilized to obtaina single best answer.

The present invention is a third method and type of apparatus that differs from the two above described in that the method and apparatus are not designed to give only one possible answer in response to the inform-ation supplied. `Instead, any one of several possibly suitable answers is given or selected. Which one of these suitable answers is selected depends upon a randomselection weighed by the probability, based on preceding events, that a particular yanswer will be selected.

The present invention is particularly suitable for cornposing music since music composition follows certain general rules and patterns, andsince there are many possible good answers. 'Ihe invention, however, is not limited to this particular use.

In practicing the invention it is rst determined, estiinated,y or arbitrarily decided, what the probabilities are that certain events, such as thesounding of certain musical notes, will follow a preceding event as, for example, the sounding ofr certain specific' notes in succession. The notes arederivedfrom sources thereof. The term sources as used herein is intended broadlyto dene any means which manifests or initiates the manifestation `of any event, such for example, as a voltage output on a specified conductor. In general, there will be a 3,007,362 Patented Nov. 7, 1961 Mice diierent probability for each of said certain events. For example, for certain kinds of music it may be that the note sequence ab may be followed by either note a, note b, or note c. There will be a certain probability that note 5 a will follow the sequence ab (such as the probability of mentsrin some ordered arrangement.

The probabilities may be stored ina matrix. vA ma- Y trix is an electrical component including circuits or ele- The arrangement may be ordered in accordance with the probabilities. The selection or choice of events may be accomplished at random as a function of the probabilities stored or established Vin the matrix.

In two specific examples of the invention described hereinafter as applied to music composition, the probabilities are determined by a statistical study of Stephen Fostermusic. The resulting music produced by the composing machine, while new, sounds like Stephen Foster type music. Y

In practicing one embodiment of the invention, a switch with multiple settings or positions, referred to yas the decode switch, is employed in combination with a random selection device. The above-mentioned probabilities are wired into the decode switch so that, following the selection of notes ab (continuing the above example and assuming two preceding cycles of operation), the apparatus will next select either a, b, or c. The decode switch provides a matrix of the type referred to above in which the probabilities are stored or established by means of the wiring or connections among the settings or positions of the switch. The decode switch will then go to the switch setting corresponding to said next selected note. The cycle is then repeated and it may be repeated indefinitely to select one notel after another. Whether said next selected note is note, a, note b, or note c depends upon the probability wiring and upon a random selection by the random selection device. In general, it may be stated that when the present invention is employed, the selection of any one event may appear to have been made at random, but on a long time average will be found to have been made in accordance with the probability of said selection.

An object of the invention is to provide an improved method of and means for selecting an event with va predetermined probability that it will follow -a certain group of events or sequence of events that precededit. The term group of events as used herein and in the claims includes the special case where the group of events consists of a single event. A further object of the invention is to provide an improved method of and means for producing or indicating an event with a predetermined probability that it will follow a certain group of events'that preceded it.

A further object of the invention is to provide a ,method of and means for selecting an event at random and also as a function of a probability that said even will follow a preceding group of events. -V

A kfurther object of the invention is to provide a method of and means for futilizing statistical dat-a for producing solutionsl based upon probabilities and random selection. Y

A further object ofthe invention is to provide an im'- proved method of and `means `for composing music.

A further object of the invention is to provide an improved method of and means for composing music having a certain resemblance to a selected type of music.

A still further object of the invention is to provide an improved method of and means for producing or indicating a sequence of successive notes of the same statistical character as employed in musical compositionsv of a selected type.

A still further object of the invention is to improved music composing machine.

A still further object of the invention is to provide an improved method of and means for providing a' random selection.

A still further object of the invention is to provide an improved random selection device.

A still fur-ther object of the invention is to provide an improved means for repeatedly making circuit connections at random. Y

A still further object of the invention is toprovide an provide an Aimproved method of and means for providing rhythm.

A still further object of the invention is to provide an improved means for producing different rhythmic pa-tterns in music. Y

A still further object of the invention is to provide an improved vacuum tube relay tree.

The invention can be better understood by referring to the specic examples illustrated in the drawings in which:

FIGURES 1a and 1b together comprise a block and circuit diagram of one specific example of the invention, the example being a music composing machine; p

FIGURE 2 is a schematic diagram of the decode switch shown in FIGURE 1;

FIGURE 3 is a circuitdiagram of the randomrswitches shown in FIGURE l; Y

FIGURE 4 is a schematicdiagram ofthe relay tree connecting into the decode switch shown in FIGURE 1;

FIGURE 5 is a schematic diagram of the rhythm controlunit shown in FIGURE l;

` FIGURE 6 kis a schematic diagram` of the relay tree incorporated in the rhythm control unit shown in FIG- URES 1 and 5; v

n FIGURE 7 is a staiI showing the twelve notes used in the example of the invention herein described;

FIGURE 8 is a dinote code table that is referred to in explaining one specilc example of the invention;

FIGURES 9a and 9b comprise a trinote probability table that is referred to in explaining one specicexample of the invention;

FIGURE l is a tabulation showing how the rhythm control unit of FIGURE functions;

FIGURE ll is a schematic diagram of a decode switch wired according to the probabilities for a dinote sequence;

FIGURE 12 is a dinote probability table from which the decode switch of FIGURE 1l was wired;

FIGURE 13 is a block Iand circuit diagram showing an lembodiment of the invention employing a plurality of decode switches;

FIGURE 14 is a schematic diagram that is referred to in explaining the circuit of FIGURE 13;

FIGURE l5 is a schematic diagram showing a portion of the switching circuit for another embodiment of the invention lemploying a plurality of decode switches;

FIGURE 16 is a block and circuit diagram of an embodiment of the invention employing a decode switch that utilizes electronic switching; p

FIGURE 17 is a circuit diagram of certain units in the decode switch employed in the system of FIGURE 16;

FIGURE 18 is a block and circuit diagram of the random switch employed in the system of FIGURE 16;

FIGURE 19 is a block diagram of the vacuum tube relay tree employed in the system of FIGURE 16;

FIGURE 20 is a circuit diagram of the apparatus contained in each block of FIGURE 19; and Y FIGURE 21 is a circuit diagram of an amplilier employed in the system of FIGURE 16.

In the several figures similar parts are indicated by similar reference characters.

Let us consider the example of the invention wherein the system of FIGURES la and lb is to compose music that will sound similar to Stephen Foster music but, at the same time, will be original music. An analysis of a group of Stephen Foster melodies, including My Old Kentucky Home, Old Folks at Home, and several others shows that there is a certain probability that a certain group of three notes (a trinote) will occur; that is, that a note following the two preceding ones (a dinote) has a certain probability of occurring depending upon the particular preceding dinote. This will be discussed more fully hereinafter. For the present, it is suflicient to note that the system of FIGURES la and 1b will play a sequence of notes in accordance with these probabilities, resulting in Stephen Foster type music.

Merely a sequence of notes is not suicient for acceptable music; rhythm must be provided. This is provided by the rhythm control unit shown in FIGURE 1b, but the addition of rhythm need not be discussed until the note sequence selection has been described.

GENERAL SYSTEM DESCRIPTION Before going into any detailed description, a brief general description of the complete system shown in FIG- .URE la will be given.

The signal frequency sources for providing the diierent musical notes may be tuning forks indicated by the blocks A-l, A42, A-3, A-4, A-6, A-8, A-9, and A-11 which supply the notes indicated on the blocks, beginning with F sharp. An inspection of Stephen Foster melodies indicates that twelve notes are suitable. As illustrated, the composing machine can play in the key of A major or D major.

To avoid duplication of tuning forks, two'octavers 61 and 62 are provided so that a fork tone may be sounded an octave higher when passed through octaver 62 than when passed through octaver 61.

Eachroctaver may comprise a clipping circuit, a frequency divider such as a multivibrator, and a shaping circuit that produces sawtooth waves. Thus the sine waves from the tuning forks are squared, divided in frequency, and converted to sawtooth waves having the desired harmonic content. The multivibrator in octaver 61 may divide byfour, and the multivibrator in octaver 62 may divide by two.

The outputs of the octavers may be fed into filters 63 for frequency spectrum control so that the successive tones as heard from a loud speaker 64 will have the desired quality. As a matter of convenience, a separate filter for each octaver may be provided, and the outputs of the lters combined.

The tone or note called for by the composing machine isA sounded in response to the energizing of one of the relays identied as relays E-l to E-12. Each relay includes an armature, shown above the relay coil, having associated with it an upper contact and a lower contact. Energizing relay E-l, for example, connects tuning fork A-6 to o ctaver 61 to sound the note b (lower octave). Energizing vrelay E-lt), for example, connects tuning fork A-8 to octaver 62 to sound the note Cit (upper octaver). The upper contacts for relays E-4 and E-12,

vrespectively, are grounded so that hum or noise cannot activate an octaver when a tuning fork is not connected to it. It will be noted, for example, that the` lead going into octaver 61 is grounded by connection through the armatures of relays E-l to E-4 until one of these relays is energized. 5,

In operation, the particular note called for rby the `composing machineisdetermined primarily by the action of two units, namely, (l) a decode lswitch unit 66, shown in .detail in FIGURE 2, and (2) a randomunit 65 comprising in combination a random switch 67 and a relay tree 68, shown in detail, respectively, in FIGURES 3 accises' and 4. VTheir design and action may be described briefly as follows: a

(1) The decode switch unit 66, in the present example, is a rotary stepping switch and a plurality of bus bars, with Vthe switch 'contact kpointsand the bus bars VVwired in accordance with the probability of a certain trinote occurring, that is, in accordance with the probability of the occurrence of a certain note following the occurrence of a certain dinote (two notes) in Stephen Foster melodies. For instance, as will be explained Yin more detail hereinafter in connection with FIGURE 2, the specific wiring illustrated and hereinafter tabulated is such that if theA machine has sounded` the noted followed by the note cti (lower case being used for the lowerv octave), then the next sounded note will be d. Thus the last three notes are the trinote d c# d. In this instance there happens to be no choice as to the last sounded note d. As to the next sounded note, there is a choice. `It may be d, or A, or e, there being different probabilities for the three possible choices. Thus the last three notes are now one of the three trinotes ci d d, citd'A, and et d e. These examples will be better understood vfrom lthe later description.

(2) The random unit' 67, 68 periodically selects one of the twelve leads of the -relay tree 68 and connects it to a relay tree lead69. Theselected lead is connected tol ground through lead 69 4each time the'rotary stepping switch of a control panel 71 steps through its positions 5 and V6. The selection of one of th'etwelve relay tree `leaclsjis purely a random choice. It is, therefore, a random note``"s'election control that is applied to the decode switch 66, but the actual note selection is in accordance with the yknown probabilities as wired into the decode switch.

'The control panel 71 comprisesl a rotary stepping switch having eight wafer sections. This switch is wired to ycontrol the sequence of,operations in the decode switch 66. It is also wired to operate the random switch 67. Note that the four right-hand wafer sections of the rotary switch connect together each of four pairs of leadsfrom-the random switch 67 when the rotary switch reaches the position shown on the drawing, This is the homing 'position'. of the rotary switch and is referred to as the No. 1 position of the six switch positions.

The Vrotary stepping switch of the control panel is moved from its No. 1 or homing position and caused to step throughV its cycle of six positions in V`response to connecting leads 72 and 73 together to energize the stepping relay 74. In operation for composing music, the leads 72 and 73'preferably are connected together periodically by `a rhythm control unit 76, which is driven continuously by a motor 77. vArmanual switch Sf-R may be provided Afor, connecting leads 72 and 73 together momentarily, if desired, to start the control panel through a sequence operation. Y Y

The rotary stepping switch-of the controlpanel makes one rotation, that is, goes through its sequence of six positions, for each note that is selected.r In the speciiic example described this one rotation occurs in 0.12 second. -Thus the manual switch S--R preferably is actuated by al two, relay combination to insure that it is held closed for less thanfOJZ-second.

With the foregoing general description in mind, the

sequence of operation for selecting and sounding a note can be followed ina general way and, therefore, will nowbe given. A full understanding of the sequence of operation will be` had-lateriollowing a more detailed circuit description. .y

OPERATION SEQUENCE (GENERAL) Assume that the control-.panel rotary switch is in the homing position, i .e., position l, as shown in FIGURE 1a. The: systemfis sounding'aapreviously selected note. The rotary switch of the rhythm control unit, and the switch S--R, are in the openpposition. Nostepping relays are operating, and nothing further will happen 6 until the leads 72 and 73 are connected together by the rhythm control unit (or by manual switch S-R). As will be understood later, during this period, as well as at all other times during thesystem operation, certain oscillators inthe random switch 67 are running continuously.

Now assume that the rhythm control unit momentarily connects leads 72 and 73 together. This momentarily applies volts D.C. to the stepping relay 74 of the control panel rotary switch through lead 75 to step the switch to position No. 2. The stepping relay 74 is now energized through wafer section-78 and a lead 79. It steps the wiper arms of the eight wafer sections through the next five positions in succession and back to the homing (No. l) position where the power supply to stepping relay 74 is broken since the No. l contact point of wafer section 78 is not connected to ground. The switch now rests on position No. l. It should be noted that the wiper arm 81 of wafer section 78 provides a make-before-break switching action as it rotates and wipes the six associatmi contact points.

Now consider the sequence, position by position, as the control panel rotary switch steps through its six positions:

t Position 1: a selected note being sounded (l) At the wafer section 82 the 110 volt A.C. supply is connected through to a lead 83 to permit energizing of any one of the decode relays (FIGURE 2) in the decode'switch 66. The wiper arm of this section is makebefore-break. i

(2) At the` wafer section 84 the lead 69 from relay tree 68 is disconnected from ground. The wiper arm of this section is make-'before-break,

.(3) At the wafer section 86 a lead 87 is connected to thehigh side of the 110 volt D.C. supply to make energizing current available to the decode switch stepping relay 88 (FIGURE 2).

' (4) At the wafer sections 91, 92, 93 and 94, the two leads of each pair of leads from the random switch 67 are connected together. as part of the sequence for making the random selection of one of the twelve leads from the relay tree 68. v

I Position 2 a (l) At wafer 82 the A.C. Supply is still connected to the lead 83.`

(2) At wafer 84 the lead 69 from the relay tree is Still disconnected from ground, and will continue to be disconnected until positionS is reached.

(3) At wafer 86 the D.C. Supply to the lead 87 is broken and remains broken through the following positions until position l is again reached, thus disabling the stepping relay 88 (FIGURE 2) of the decode switch.

(4) At the wafer sections 91, 92, 93, and 94 the connections between pairs of leads from random switch 67 are. broken whereby the random selection of one of the twelve leads from relay tree 68 is made. The connections between pairs of leads remains broken until position l is again reached.

Position 3:

Position 4 (1) At wafer 82 the A.C.v supply is aigain connected to lead 83 to permit energizingof the decode relays (FIG- URE `2), and will continue to be so connected until posi- Y tion 3 is again reached.

(2) At wafer 84 relay tree lead 69 is still ungrounded. 

